ISDN-, LAN- and Analogue Installation Techniques - EPV

Transcrição

ISDN-, LAN- and Analogue Installation Techniques
Application-independent Wiring Systems according to European Standard EN 50173-1
8.5.1.2
65
Plug-in Connectors for Category 7 / Class F
In EN 50173-1 (Plug-in Connector section), reference is made to two different connector systems for
cabling in the 600 MHz range (Category 7 / Class F):
!
!
the fully screened TERA™ Connector (standardised to EN 61076-3-104)
the RJ 45-compatible GG45™ Connector (standardised to EN 60603-7-7)
TERA™ Connector
This multimedia connector, developed by the Siemon Company, is the first kind available on the market
for Category 7 cabling systems. It is so efficient that several applications, such as voice, high-speed
network services and broadband video, can all use the same cable, simultaneously (‘Cable Sharing‘).
The enormous flexibility of the TERA™ connector is due to its 1-, 2- and 4-pair modularity, whereby it is
possible to patch each pair, individually.
The TERA™ system not only supports 10 Gbit/s, but also offers double the bandwidth than that described
in the specification of the current Category 7 / Class F (1,2 GHz!). Thus, the transmission of multimedia
services, such as cable TV in the frequency range of 862 MHz, does not present any problems.
Fig. 8.7: TERA™ connector, 4-, 2- und 1-pair versions for
simultaneous transfer of services via separate pairs
Fig. 8.8: 4-pair TERA™ socket
(both photos: Siemon)
GG45™ Connector
A GG45™ system, developed by Nexans, is a connector for
bandwidths up to 600 MHz and above, standardised
according to EN 60603-7-7.
© 2006 by EPV Elektronik-Praktiker-Verlagsges. mbH
The special feature of this connector is the downwards
compatibility to the categories 5 and 6 (Classes D and E)
for applications in a frequency range up to 250 MHz. So
with this »2-in1« connector, the conventional reasonably
priced, RJ 45 jumper cable can be used and when a better
performance is needed (Cat. 7), the RJ 45 jumper can be
simply replaced by the GG45 cable.
This solution is achieved by the use of 4 additional contacts
(the plug has a total of 12 contacts = 8 connections = 4
pairs) and an internal switch that, depending on the plug
being used (RJ 45 and GG45), switches between Classes
D and E applications and Class F performance.
Fig. 8.9: GG45™ connector with
RJ 45 adapter (photo: Nexans)
66
1
2
1
2
3
3'
Switch
4
4
4'
5
5
Contacts
Connections
3
5'
6
Fig. 8.10: GG45™ socket
(Nexans)
6'
7
8
7
8
Fig. 8.11: Internal switch setting when using
GG45™ plug
For technical reasons, when preparing
GG45™ plugs, the contacts must be
assigned according to EIA/TIA 568B
(c.f. Fig. 8.15).
In Cat. 7 cabling (with GG45™ jumper
cords), the contact assignment shown
in Fig. 8.12 is used.
Pair 3
Pair 4
12
78
3'6'
4'5'
Pair 1
Pair 2
Fig. 8.12: Contact assignment for a Cat. 7
GG45™ connector
Requirements on Installations with LANmark-7
GG45™ Cabling systems (Nexans)
Because of the high technical standards demanded and
the complexity of Class F / Cat. 7 systems, the preparation, installation and the concluding completion of
measurements, require a strict compliance with installation guidelines.
Since with an installation of GG45 cabling systems a longterm guarantee is also associated, the manufacturer
Nexans has a prerequisite that a special NTI course of
instruction be completed (»Nexans Trained Installer«)
before an installation may be commenced as well as
taking delivery of their LANmark-GG45 products.
Topics (theory/practise) of this one day certification
course:
!
!
!
!
Fig. 8.13: Author‘s NTI certificate
Standards
Preparation of terminal devices
Measurement techniques
Fault rectification
"
6
Contact and Colour-coding of an RJ 45 Connector,
for Structured Cabling in Buildings
To ease the task of connecting the wires of the
installation cable, the connections on the socket are
numbered and/or identified by colouring to match the
cores of the cable. Reference should always be made
to the relevant manufacturer‘s data sheets.
EN 50173-1 recommends connections in pairs for the
8-pin socket, but without any fully numbered pairing
sequence. In practise, the pin allocation as recommended in the American EIA/TIA 568 A-Norm has
become the standard.
12 3 4 5 6 78
8 7 6 5 4 3 2 1
RJ 45 socket
RJ 45 plug
Fig. 8.14: Contact numbering of
RJ 45 sockets and plugs
Pair
Colour-coding of
paired wires
Colour-coding,
English
Contact assignment,
EIA/TIA 568A
1
Blue
White/Blue
BU
WH/BU
4
5
2
Orange
White/Orange
OG
WH/OG
6
3
3
Green
White/Green
GN
WH/GN
2
1
4
Brown
White/Brown
BN
WH/BN
8
7
Pair 2
Pair 3
White-Brown
White-Blue
Brown
Pair 4
Pair 1
White-Green
Blue
Pair 2
White-Orange
Orange
White-Blue
Orange
White-Brown
Brown
Pair 4
Pair 1
White-Green
Green
White-Orange
Blue
Pair 3
Green
8.5.2
67
1 2 3 4 5 6 7 8
EN 50173-1 (if only 2 pairs per
connection are used, then 4/5 and
3/6). Colour-coding not specified
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
EIA/TIA 568A
EIA/TIA 568B
Fig. 8.15: Example of contact assignment and colour-coding, 8-pin RJ 45 socket (front view)
When selecting a pin assignment for connections in a particular system, it is of no importance which
standard is used for the cabling. It is important however, that the same assignment is used at the
patch panel and at the junction boxes. The most used method is the assignment according to
EIA/TIA 568A, since the pairing conforms to EN 50173-1.
The voice, data or video services used in structured cabling systems, do not require all 8 contacts of an
RJ 45 connector. Most services require 2 pair using different contacts, for data transfer. But, the object
of a neutral cabling system, independent of the type of application, is to achieve a universal usage that
is independent of services provided. Therefore, it is recommended to install all 4 pairs.
68
Table 8.4 shows which services are assigned to which contacts:
Telephone
analogue
ISDN
Pair 3
Token Ring
ATM
S
S
S
(S)
S
TD+
1
Pair 1
FDDI
(TP-PMD)
IS 400 (IBM) 3270 (IBM)
(S)
(S)
S
X
TD-
2
Pair 4
Pair 2
Ethernet
10/100
Base T
TD+
X
RD+
TD-
3
W
RD+
RD+
4
a
TD+
TD-
TD+
5
b
TD-
TD+
TD-
6
E
RD-
RD-
RD+
TD+
TD-
RD-
RD-
7
X
RD+
8
X
RD-
RD
TD
S
FDDI
TP-PMD
=
=
=
=
=
Received Data
Transmitted Data
Shield or Screen
Fibre Distributed Data Interface
Twisted Pair - Physical Media Dependent
Table 8.4: Contact assignment for various services
1
2
3
4
5
6
7
8
Ethernet
10/100 Base T
1
2
3
4
5
6
7
8
Token Ring
ISDN
1
2
3
4
5
6
7
8
FDDI (TP-PMD)
ATM
Fig. 8.16: Showing the contact assignment for various services (RJ 45 junction boxes)
8.5.3
Patch Panel (or Board)
Also known as a distribution panel or twisted-pair distribution frame.
"
The height of the patch panel is given in height units (HU).
One height unit corresponds 1¾“ (44.45 mm).
A patch panel can be regarded as a plug-in field used for the connection, distribution or jumpering of
data cables (also applies to fibre optics). Patch panels are incorporated in 19“ distribution cabinets.
Each junction box in the horizontal level is allocated its own RJ 45 plug.
69
The usual number of RJ 45 junction boxes in each HU, is 16 to 24. Patch panels are also available with
RJ 45 modular sockets (jacks). Here, the number of RJ 45 connectors varies.
Also well-known manufacturers offer patch panels that can be fitted with RJ 45 jacks as well as fibre
optic connectors.
Most patch panels include labelling fields that are very necessary for correct documentation of a system.
44.45
Labelling field
1
2
3
4
5
14
15
16
465.1 mm
Fig. 8.17: Example of a patch panel with one height unit (1 HU) and 16 RJ 45 sockets
Patch panels are also available for connecting and
distributing FO cables and Cat. 7 data cables.
Fig. 8.18: Patch panel for Tera connectors (Photo: Siemon)
8.5.4
Patch Cables
Also sometimes known as jumper cables or cords, they
are screened symmetrical copper cables that must be
highly flexible.
In contrast to installation cables, jumper cords consist of
stranded wire (e.g. 7 x 0.16 mm2).
The screening can take the form of:
!
!
!
!
Foil
Mesh
Both foil and mesh
Pairs in foil with an overall mesh
Fig. 8.19: Patch cables with RJ 45 plugs
70
8.6
Distribution Cabinets for Structured Cabling
8.6.1
Requirements in a Distribution Cabinet
!
Description: 19-inch cabinet or networking cabinet or data cabinet
!
It is at the heart of any structured cabling system.
!
These cabinets house distributors (hubs and switches) and patch panels, installed as
sub-assemblies.
!
Usually, there is also enough space to store other products that do not conform to the 19“
standard (e.g. monitors, keyboards, handbooks, external disc drives, etc.).
!
It is also possible to integrate the ISDN PBX and server (mainframe computer).
!
Outer dimensions of the mounting frame = 19“ = 482.6 mm
(hole separation of screw fixings for component mounting = 465.1 mm)
!
Cabinet base area, usually 80 x 80 cm
!
Cabinet height 90 to 220 cm (internally, up to approx. 46 HU)
(During planning phase, allow for some reserve space in height.)
!
Protection functions:
Body contact protection (against parts carrying a voltage)
Protection against entry of foreign bodies
Water protection (also, splash-proof and protection from steam)
Protection class IP55 (for office rooms, IP40 and IP54 are sufficient)
Strong padlocks as mechanical protection (access only for authorised persons)
!
Handling:
Side walls and doors should be removable
The front door should be locked, and possibly one of the side walls or the back panel
!
Cable entries:
Suitable openings should be available at the top or rear together with internal
cable runs
!
Additional equipment required:
Air conditioning
Tilt and swivel frame for mounting sub-assemblies
Cabinet lighting
Window in doors or sides
To ensure a simple method of identifying connections, some manufacturers offer their own type of cables
with different colours for the sheath (usually 5). Jumper cords should be matched to the cables used
for the cabling installation. It has shown to be an advantage to select jumper cords and installation
cables from the same manufacturer.
Latitute C Pi
Latitute C Pi
71
Latitute C Pi
terminal
devices at
workplaces
Patch panel
Jumper cablel
Telephone system / PBX
Incoming line
Incoming line
Hub / Switch
Hub / Switch
19" distribution cabinet
mainframe computer
UPS Un-interruptible
pow er supply
Fig. 8.20: Function schematic of a structured cabling system
8.6.2
Requirements in an Engineer‘s Room
An engineer‘s room (or distribution room) is the usual place for locating the distribution cabinet.
The following requirements should be borne in mind:
-
Solid flooring and lockable door
All sides of the distribution cabinet must be freely accessible
10 to 15 m2 of floor area
Separate, fused, power supplies
Sufficient number of mains outlet sockets
Telephone, independent of the distribution cabinet
Good lighting for installation work
Ambient temperature of 10° to 40°C
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8.7
SOHO (Small Office Home Office)
As described at the start of this chapter, the field of application for cabling systems according to the
EN 50173-1 standard, is optimised for locations where the maximum distance for the distribution of
services, is 2 km. The methods in the European standard may also be used for larger installations.
To meet all the requirements of small and medium-sized businesses, including homeworkers, for technical
information and communications systems, several manufacturers offer so-called SOHO solutions (Small
Office Home Office). These systems are mainly for small installations (usually up to 8 connections),
modular extendable, cabling systems with components as 10“ or 19“ rack units with 1 or 3 HU‘s,
respectively.
Abb. 8.21: Engineer completing measurements with a »DTX 1800« (Photo: Fluke Networks)
8.8
Measurements on Structured Cabling Systems
The use of cables and junction boxes rated as class D, E or F, is no guarantee that after the installation,
the network conforms to the classes mentioned.
"
For measurements on structured communications cabling systems, the EN 50346 standard
»Testing Installed Cabling« applies.
The engineer responsible for the installation, must measure every link in the network.
After completing a cabling installation, every customer expects measurements and tests to be made of
the system before signing a certificate of acceptance. This is because 10% of all errors occur during the
installation of the wiring.
8.8.1
73
Test Instruments
Measurements on a copper cable network are made with a so-called TDR meter (Time Domain
Reflectometer), where an electric pulse is injected into the cable and the meter evaluates the reflected
signal. A similar measurement principle is used for fibre optic networks, except that here, a light strobe is
sent along the fibre optic cable and the reflected light is evaluated with an OTDR meter (Optical Time
Domain Reflectometer).
A few suitable test instruments (copper networks) are listed below:
Name of the Test Instrument
Manufacturer
LANTEK 6, 7 & 7G (7G: up to 1000 MHz)
NAVITEK (suitable for beginners)
DTX 1800 series (up to 900 MHz)
Validator-NTTM (up to 1000 MHz)
LanScaper (suitable for beginners)
Ideal Industries
Ideal Industries
Fluke Networks
Test-Um Inc.
Test-Um Inc.
For simple operation and to save time, most models incorporate an
»Autotest Function«, that by pressing a button, all parameters for
measurement, are detected. Using the »Validator NT™« from Test-Um
Inc. as an example, the following parameters are measured automatically:
!
!
!
!
!
!
Connections
!
Distance to opens and shorts
Cable length
!
BERT
Attenuation
!
NEXT - all combinations
ACR
!
Impedance mismatches
Return loss
!
Reserve (Headroom)
SKEW (Propagation time & Difference)
Fig. 8.22: »Validator NT™«
(Photo: Test-Um Inc.)
Informatics connection
Work
station
Collective point (option)
Start of channel link / TIA/EIA
Start of tranfer line / ISO/EN
Installed line
Floor
distributor
Patch panel
End of channel link / TIA/EIA
End of tranfer line / ISO/EN
Fig. 8.23: Measurements of a transfer line (Illustration: Ideal Industries)
74
8.8.2
Main Parameters for Characterising a TP-cabled Line
No.
Parameter
Short explanation
1
Characteristic impedance [#]
Impedance of the cable.
All parameters of the line have an effect on
the impedance (line DC resistance, insulation resistance, capacitance and inductance
of the line).
2
DC loop resistance [#]
DC resistance of the length of copper cable
(loop), that has been installed.
3
Attenuation [dB]
Describes the logarithmic relationship between output power and input power on a
transfer line. A lower attenuation results in
more power being available at the end of the
transfer line.
4
Near-end crosstalk attenuation NEXT [dB]
This value describes the unwanted breakthrough of electrical energy from one information line to the other. A high value of crosstalk attenuation in dB, indicates less interference from crosstalk.
5
Attenuation Crosstalk Ratio (ACR) [dB]
Describes the relationship between signal
attenuation and near-end crosstalk attenuation (dB difference = signal-to-noise ratio).
8.8.3
Parameters and Limit Values (capabilities of symmetrical transfer lines)
according to EN 50173-1 (Europe), IEC 11801 (international) or
TIA/EIA 568 B.1 / B.21 (North America)
Instead of discrete values for particular frequencies, the limit values of the parameters given in Table 8.5
are the basis for the formulae used. The formulae are included in section 5 of the standards given above.
They provide the guiding principles for the standards. There are also limit values given in the standard,
that are included in the list.
Remarks to TIA/EIA 568 B.1 / B.21:
Originally, TIA/EIA specified unscreened copper connection components. TIA/EIA are not normal standards, they
are an industrial specification that apply to the North American market. They also include the requirements set out
in EN or ISO/IEC for the transfer properties of cabling and components.
14,4
25
Near-end crosstalk ( NEXT ) [dB]
Power summed near-end
crosstalk (PSNEXT) [dB]
Attenuation to crosstalk ratio
(ACR) [dB]
Power summed ACR [dB]
Equal level far end crosstalk
(ELFEXT) [dB]
Power summed ELFEXT [dB]
DC loop resistance [#]
Propagation time [µs]
Largest propagation time
difference [µs]
Earth-symmetry attenuation [dB]
Coupling attenuation [dB]
4.
5.
6.
9.
10.
11.
12.
13.
14.
15.
8.
7.
Characteristic impedance [#]
Smallest return loss attenuation
[dB]
Maximum attenuation [dB]
2.
3.
No specifications
No specifications
0,050
0,546
25
12,3
15,3
– 5,8
– 2,8
37,1
33,1
35,9
0,030
0,545
25
28,3
31,3
– 6,4
– 3,4
59,9
51,2
54,6
Comments
Here, the attenuation α, of one pair in the transfer path is
measured
The crosstalk attenuation is measured between all pair
combinations in the transfer path
PSNEXT must be retained for all pairs in the transfer path
(at both ends)
The ACR of a pair is calculated from the NEXT between
the pairs and the attenuation of one pair
The PSACR of a pair is calculated from the PSNEXT and
the attenuation of the pair. The parameter must be the
same at both ends
The ELFEXT of a pair is calculated from the FEXT
attenuation of the pair and the attenuation of a pair
PSELFEXT of a pair is measured for each pair. The
PSELFEXT of the faulty pair is calculated from ELFEXT
(in pairs) between neighbouring pairs
The difference in the DC resistance between the 2 wires
in each pair must not exceed 3% for the classes given
The propagation time of all pairs must be less than the
given limit values. Measurements are made only when
requested.
The difference in the propagation times of all pairs must
be less than the given limit values. Measurements are
made only when requested
The earth-symmetry attenuation must be achieved by
selection of cable and connections. Measurements above
80 MHz are still under discussion.
Measurement of the coupling attenuation is still in
preparation. At present, measurements are made, only in
the laboratory.
No tolerances given
Must be retained at both ends of the cable
Applies to all classes
Table 8.5: Parameters and limit values according to EN 50173-1
0,050
0,548
17,4
3,1
6,1
27,1
30,1
24
Length of transfer line; Link; [m]
1.
Limit values
Class D
Class E
Class F
at 100 MHz
at 250 MHz
at 600 MHz
100 m, including 2x 5m incoming links
(equipment connection and patch cables)
In general, 100 #
12,0
8,0
8,0
Parameter [units]
No.
75
76
Notes on Installing Structured
Cabling Systems
"
Data cable must be handled with care at all times,
before, during and after the installation.
!
Before commencing with the installation, check the following:
- Has the correct cable been delivered?
- Has any damage been caused during transit?
- Does the cable match the connection components (junction boxes, etc.)?
!
Store the data cable only in a dry room (dampness or humidity, affects the electrical data
of the cable).
!
When laying cables, they must not be subjected to mechanical distortion (squashing,
pressure, tension).
!
Remove any rough edges from cut-outs before laying the cables.
!
Pay attention to the cable bending radius specified by the manufacturer (usually, at least
8x the external diameter of the cable).
!
Avoid uncoiling too much cable before feeding the cable through openings. If possible, lay
the cable directly from the cable reel. Do not use excessive force when pulling the cable.
!
Do not pull the cable over the side of the reel (danger of twisting the cable, distorting the
internal structure and changing its electrical parameters).
!
If it is necessary to pull the cable, ensure that all cores are pulled with the same tension.
8.9
77
!
If it is evident that moisture has penetrated the cable end, the relevant end must be cut-back at
least 50 cm.
!
To ease the task of inserting cables in small openings, it is permitted to use a lubricant (e.g. soft
soap, washing-up liquid, or similar - not oily substances!).
!
Do not use hot air for working the cable (e.g. hairdryer).
!
Never install data cable with power cables in the same cable duct.
Use separator plates!
!
When laying the cable, do not open the cable twisting too far (max. 13 mm) and do not re-twist
the cables (danger of increasing the NEXT value).
!
Ensure that the screening is well-spread (360°) in the area of the cable connections.
!
Screened line networks and all metal components (sill-type or cornice, trunking, distributor
cabinets, etc.), must be connected to the equipotential bonding of the building.
9
The Contact Principle LSA-PLUS ®
Das LSA-PLUS system with the LSA-PLUS insertion tool and contacts, developed by the Krone Company
in Berlin, Germany, provides a method of connection, separation, change-over and grounding wires in
telephone and data installations.
LSA-PLUS is a registered trade name in Germany and is based on the abbreviation of a German
description of the system. Every year, millions are produced and sold in 80 countries throughout the
world.
The LSA-PLUS contacts are extremely reliable and result in very good contact properties, in all climatic
conditions. The system uses insulation piercing techniques that result in an absolute tight electrical
connection between the LSA-PLUS contacts and the plastic-insulated copper core of the cable. It is not
necessary to remove the insulation from the cable end and, after completing the insertion, a contact is
produced that is not influenced by any mechanical vibrations or corrosion.
This principle of contacting applies from a simple junction box on to patch panels and floor distributors in
a structured cabling system, and is used by almost all manufacturers.
Fig. 9.1: LSA-PLUS contact strip

ISDN-, LAN- and Analogue Installation Techniques - EPV

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